When faced with the success of the underfloor engined Volvo Citybus, Leyland designed their own model based on an existing DAB design. The first vehicles saw the light of day in 1986. The model proved unpopular with operators, selling only 32 examples before being withdrawn in 1989. Those delivered to Eastern were all bodied by Alexander & look very similar to Volvo Citybuses delivered at the time, although they are slightly taller & the front overhang is noticeably longer.

ZLL177 was one of the first batch of Lions delivered and was initially used in conjunction with the 1986 Commonwealth Games held in Edinburgh. After the games it settled down to life at Musselburgh depot where it worked services 124 and 129. Because the bus has a highbridge body, it was unable to operate on the Dunbar service. During the mid 1990s, the bus was transferred to Livingston where it worked the busy routes to and from Edinburgh before being returned to Musselburgh.

In 1990 Eastern was sold to its management who quickly readopted the SMT fleetname. In order to improve the company's image the routes linking West Lothian and Edinburgh were branded 'Diamond Routes' & ZLL177 was repainted & reallocated to Livingston. In 1994 GRT Holdings bought the company & quickly set about rationalising their three local subsidiaries, resulting in the SMT fleet being split between Midland & Lowland. ZLL177 became 1177 in the Midland fleet. Further reorganisations followed over the next 5 years with the bus eventually returning to Musselburgh, being numbered 1977 & forming part of the First Edinburgh fleet. The bus was returned to Livingston in 2004 & was withdrawn from service during 2005. By the time of withdrawal, C177 VSF had acquired First fleetnumber 31691.

ZLL177 is the only surviving Leyland Lion from the original batch of 13 vehicles. Its present owners bought the bus in early 2005 and have restored it to largely original condition. This involved a great deal of restoration work to recondition parts of the engine as well as having a bodywork overhaul before repainting into the original livery of green and cream.